In the previous lesson, we did some simple math in a spreadsheet – we started with two values, then computed their sums and averages.Let’s recap where we left off with the sum of the numbers in two cells, **A1 and B1**. We learned that the formula that computes this sum simply refers to, or “points to,” the values in these cells by using the cell locations (or we can call it the “cell name,” or “cell label.”)

So in cell **A2**, we typed in

=SUM(A1:B1)

and we ended up with the sum of two numbers. Whenever we change what’s in A1 or B1, the sum changes too.

Now what if we added a couple more numbers in cells A3 and A4, and we wanted to figure out how to get their sum. Think a bit about what that formula looks like.